Methods and devices for improving percutaneous access in minimally invasive surgeries

ABSTRACT

A device for use as a portal in percutaneous minimally invasive surgery performed within a patient&#39;s body cavity includes a first elongated hollow tube having a length adjusted with a self-contained mechanism. The first elongated tube includes an inner hollow tube and an outer hollow tube and the inner tube is adapted to slide within the outer tube thereby providing the self-contained length adjusting mechanism. Two or more elongated tubes with adjustable lengths can be placed into two or more adjacent body cavities, respectively. Paths are opened within the tissue areas between the two or more body cavities, and are used to transfer devices and tools between the adjacent body cavities. This system of two or more elongated tubes with adjustable lengths is particularly advantageous in percutaneous minimally invasive spinal surgeries, and provides the benefits of minimizing long incisions, recovery time and post-operative complications.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/186,619, filed Feb. 21, 2014, which application is a continuation ofU.S. application Ser. No. 13/100,640, filed May 4, 2011, whichapplication is a divisional application of U.S. application Ser. No.10/868,075, filed Jun. 15, 2004, which claims the benefit of U.S.Provisional Application No. 60/518,580, filed on Nov. 8, 2003, thedisclosures of which are hereby incorporated herein by reference.

This application relates to U.S. application Ser. No. 10/669,927, filedon Sep. 24, 2003, the disclosure of which is hereby incorporated hereinby reference.

FIELD OF THE INVENTION

The present invention relates to methods and devices for improvingpercutaneous access in minimally invasive surgeries, and moreparticularly to methods and devices that provide variable length accesschannels to locations deep within a patient's body, and allow thepercutaneous transfer of connecting devices and instruments within oneaccess channel or between two or more adjacent access channels placeddeep in two or more locations of the patient's body, respectively.

BACKGROUND OF THE INVENTION

The present invention relates to methods and devices for improvingpercutaneous access in minimally invasive surgeries, and moreparticularly to methods and devices that provide variable length accesschannels to locations deep within a patient's body, and allow thepercutaneous transfer of connecting devices and instruments within oneaccess channel or between two or more adjacent access channels placeddeep in two or more locations of the patient's body, respectively.

It is well known that traditional surgical procedures in locations deepwithin a patient's body require a long incision, extensive musclestripping, prolonged retraction of muscles for visualization, anddenervation and devascularization of the adjacent tissue. Theseprocedures result in extensive tissue traumatization and consequently inprolonged recovery time, risk of infections, high hospitalization costs,pain that can be more severe than the pain due to the initial ailment,and in some cases permanent scarring. In minimally invasive surgicalprocedures, portals are used to access the locations deep in thepatient's body. The use of portals rather than a long incision causesless trauma to the adjacent tissue, reduces the recovery time and painand may be performed in some case under only local anesthesia. Theavoidance of general anesthesia reduces post-operative recovery time andthe risk of complications.

Minimally invasive surgical procedures are especially desirable forspine surgeries because spine pathologies are located deep within thebody without clear muscle planes and there is danger of damaging theadjacent neural and vascular tissues. In treating the majority of spinalpathologies, the spinal muscles are stripped from the bony elements ofthe spine followed by laminectomy to expose the dura, the nerve roots,and the discs. The incision has to be wide enough and the tissues haveto be retracted to maintain a channel from the skin to the floor of thespinal canal that will allow direct visualization. This is similar to anopen surgery approach to the knee to expose the menisci versus minimallyinvasive alternatives such as an arthroscopy which uses 1 centimeterportals under illuminated magnification which results in improvedvisualization, reduced postoperative knee pain, recovery time, and thedestruction of healthy tissue. The destruction to the spinal structuresis even more extensive during fusion procedures, which require morelateral tissue dissection and exposure to access the transverseprocesses and pedicles for placement of pedicle screws, rod constructsfor stability, and bone graft under direct vision.

Multiple attempts have been made to improve the techniques, devices, andinstrumentations used for minimal and percutaneous surgery. Theseinclude use of percutaneous needle administration of chemonucleolyticagents to enzymatically dissolve the disc and the use of microscopes andloupe magnification to limit the incision size. These two approaches areat the foundation of minimal access surgery, one using an injectableagent and the other using a device to limit the exposure whilemaximizing the visualization. Unfortunately, the effectiveness andsafety of the enzyme, chymopapain used for chemonucleolysis, have beencomplicated by severe spasms, post-operative pain, and sensitivityreactions including anaphylactic shock. Loupe magnification andmicroscopes are helpful for improving visualization but are noteffective without retractor systems and specialized instruments anddevices to make minimal access surgery effective.

Substantial progress has been made to develop the necessary devices,instruments, and methods to effectively improve minimal access surgeryresulting in improved visualization, less tissue injury, less generalanesthesia exposure and improved recovery time and post-operative pain.For example U.S. Pat. Nos. 5,792,044 and 5,902,231 by Foley et al.,demonstrate some of the improved methods and instruments forpercutaneous surgeries.

A problem that occurs frequently in minimally invasive surgicalprocedures is related to the fact that it is not always known how deepthe pathology is located. Accordingly there is a need for a portal witha variable length to accommodate the locations of the variouspathologies.

Furthermore, in spine fusion procedures connecting elements, such asrods, plates or wires are placed and fixed between two or more locationsof the spine. Placement of these connecting elements requires opensurgery, which is currently one of the major limitations of otherpercutaneous cannula access methodologies. Accordingly there is a needfor inserting and placing these connecting elements between two or moreseparate spinal locations without performing open surgery.

SUMMARY OF THE INVENTION

In general, in one aspect, the invention features a device for use as aportal in percutaneous minimally invasive surgery performed within apatient's body cavity. The device includes a first elongated hollow tubehaving a proximal end and a distal end and defining a first workingchannel between the proximal end and the distal end when placed withinthe body cavity. The first tube has a mechanism for adjusting the lengthof the first tube within the patient's body cavity.

Implementations of this aspect of the invention may include one or moreof the following features. The first tube includes an inner hollow tubeand an outer hollow tube and the inner hollow tube is adapted to slidewithin the outer hollow tube thereby providing the mechanism foradjusting the first tube length. The inner hollow tube comprises anouter surface having an elongated groove extending along a lengthsegment of the outer surface, the outer hollow tube comprises an innersurface having an elongated appendage extending along a length segmentof the inner surface, and the appendage is adapted to slide within thegroove thereby providing the mechanism for adjusting the first tubelength. The inner hollow tube comprises an outer surface having anelongated appendage extending along a length segment of the outersurface, the outer hollow tube comprises an inner surface having anelongated groove extending along a length segment of the inner surface,and the appendage is adapted to slide within the groove therebyproviding the mechanism for adjusting the first tube length. The innerhollow tube comprises a first slot opening extending the entire width ofthe inner hollow tube, the outer tube comprises a second slot openingextending the entire width of the outer hollow tube and the first slotopening is aligned with the second slot opening when the inner hollowtube is assembled within the outer hollow tube, thereby forming acontinuous opening extending the entire width of the first tube. Thefirst tube further comprises a second hollow tube extending from a sideopening of the first tube located outside the body cavity and forming asecond working channel and wherein the second working channel is incommunication with the first working channel through an opening in thewall of the outer hollow tube. The first and second tubes are sized fordelivering carrier devices, surgical instruments, medical devices,fixation devices, vertebral disc replacement devices, interbody devices,fixation tools, connecting devices, connecting tools, tissue, graftingmaterial, or illumination devices, to a pathology location within thebody cavity. The surgical instruments may be scissors, scalpels, saws,drills, tissue dilators, biting and grabbing instruments, curettes, knottying, or cautery. The fixation devices may be screws, hooks, loops,pins, nuts, washers, wires, sutures, or staples. The fixation tools maybe screw drivers, pushers, holders, wrenches, staplers, or knot tiers.The connecting devices may be plates, rods, wires, vertebral discreplacements, interbody fusion devices, or articulating versionsthereof. The connecting tools may be connecting tools carriers, pushers,screw drivers, and wrenches. The illumination devices may be lightsources, fiber optic cables, infrared detectors, magnification devices,and microscopes. The first tube may further comprise a mechanism forengaging and disengaging a fixation device. The first tube may comprisea slot at the distal end and the slot is sized to engage an appendage ofthe fixation device and secure the fixation device through a clock-wiserotation around a longitudinal axis of the first working channel,thereby providing the engaging mechanism for engaging the fixationdevice. The device may further comprise disengaging the fixation deviceby performing a counter-clock-wise rotation around the longitudinalaxis. Alternatively, the first tube may engage or disengage theappendage of the fixation device via an anti-clockwise rotation or aclockwise rotation, respectively. The continuous opening may be sizedfor delivering surgical equipment, medical devices, intervertebral discreplacement devices, interbody fusion devices, fixation devices,fixation tools, carrier devices, connecting devices, connecting tools,tissue, grafting material, or illumination devices, from the firstworking channel of the first elongated tube to a first working channelof second elongated tube located adjacent to the first elongated tube.The carrier devices may comprise flexible, malleable, rigid, ormaterials that are expandable at body temperature. The inner or theouter hollow tubes may comprise a taper along their length. The firsttube may further comprise a manually adjustable mechanism for adjustingthe first tube length within or outside the body cavity. The outercannula may have millimeter markers etched on the outside to allow theuser to determine the depth of the pathology with respect to the skinsurface. The first tube may comprise an inner hollow tube having anouter cylindrical surface with a first set of helical threads and anouter hollow tube having an inner cylindrical surface with a second setof helical threads. In this case, the outer hollow tube is adapted torotate around the inner hollow tube while engaging the second set ofhelical threads with the first set of helical threads, thereby causingthe inner hollow tube to move longitudinally relative to the outerhollow tube and thereby providing the mechanism for adjusting the lengthof the first tube. The inner hollow tube may be adapted to slide withina space formed between an inner cylindrical wall and an inner planarwall of the outer hollow tube. The inner hollow tube may be adapted toslide within a space formed between an inner cylindrical wall of theouter tube and an outer cylindrical wall of a second hollow tube placedconcentric with the inner and outer hollow tubes.

In general, in another aspect the invention features a system for use inminimally invasive percutaneous surgery including two or more elongatedhollow tubes placed within two or more adjacent body cavities of apatient, respectively. Each of the two or more hollow tubes comprises aproximal end and a distal end defining a first working channel betweenthe proximal end and the distal end and at least one of the two or morehollow tubes comprises a mechanism for adjusting its length.

Implementations of this aspect of the invention may include one or moreof the following features. The two or more hollow tubes define two ormore first working channels, respectively, and the two or more hollowtubes comprise two or more side openings extending the entire width ofthe two or more tubes, respectively, and the two or more side openingsare aligned with each other and are sized for allowing transferring ofobjects between the two or more first working channels. The objects maybe surgical equipment, medical devices, intervertebral disc replacementdevices, interbody fusion devices, fixation devices, fixation tools,carrier devices, connecting devices, connecting tools, tissue, graftingmaterial, or illumination devices. The two or more side openings arelocated in areas of the two or more tubes, respectively, positionedwithin the two or more adjacent body cavities, respectively. The systemmay also include a carrier device for transferring devices between thetwo or more elongated hollow tubes through the aligned side openings.This carrier device may be made of a material that is stiff, malleable,flexible or expandable at body temperature. The system may furtherinclude direct or indirect visualization of the two or more firstworking channels.

In general, in another aspect the invention features a method forperforming percutaneous minimally invasive surgery on a patientincluding inserting a first elongated hollow tube within a first bodycavity of the patient, wherein the first tube has a proximal end and adistal end and defining a first working channel between the proximal endand the distal end when placed within the first body cavity and whereinthe first tube comprises a mechanism for adjusting the first tube lengthwithin the first body cavity.

Implementations of this aspect of the invention may include one or moreof the following features. The method may further include beforeinserting the first tube into the first body cavity making a firstincision on a first location of the patient's skin, then advancing afirst guide wire through the first incision, through tissue underlyingthe first location and into a first underlying bone and forming thefirst body cavity around the first guide wire. The first body cavity isformed by advancing a tissue dilator over the first guide wire. Themethod may further include placing a fixation device over the guide wireand engaging the distal end of the first tube to a fixation device inthe first body cavity. Alternatively, the method may further includeengaging a fixation device to the distal end of the first tube beforeinserting the first tube into the first body cavity, then attaching thefixation device to a first bone within the first body cavity afterinserting the first tube into the first body cavity and disengaging thefixation device from the distal end of the first tube. The method mayalso include adjusting the first tube length via a self-containedadjusting mechanism. The first tube comprises an inner hollow tube andan outer hollow tube and wherein the inner hollow tube is adapted toslide within the outer hollow tube thereby providing the self-containedmechanism for adjusting the first tube length. The method may alsoinclude inserting a cutting tool into the first tube and incising tissuearound the first body cavity. The first tube comprises a first openingextending the entire width of the first tube and being located in aportion of the first tube within the first body cavity and wherein thecutting tool is used to incise tissue around the first body cavitythrough the first opening. The method may also include inserting asecond elongated hollow tube within a second body cavity of the patientadjacent to the first body cavity, wherein the second tube has aproximal end and a distal end and defining a second working channelbetween the proximal end and the distal end when placed within thesecond body cavity and wherein the second tube comprises an adjustablelength. The method also includes incising tissue between the first bodycavity and the second body cavity, thereby forming a path extending fromthe first body cavity to the second body cavity, then inserting aconnecting device into the first tube and then transferring theconnecting device from the first tube to the second tube through thepath. The method also includes attaching a first end of the connectingdevice to a first bone within the first body cavity via a first fixationdevice and attaching a second end of the connecting device to a secondbone within the second body cavity via a second fixation device. Thefirst bone within the first body cavity may be a first vertebra, and thesecond bone within the second body cavity may be a second vertebra. Thefirst and second fixation devices may be screws, hooks, loops, pins,nuts, washers, wires, sutures, or staples. The connecting device may beplates, rods, wires or articulating versions thereof. The connectingdevices may be transferred within a carrier device and the carrierdevice may have a boat-shaped body with a closed front end. The tissuebetween the first and the second body cavities may be a lumbodorsalfascia and the path is located either above or below the lumbodorsalfascia. The first and second tubes are sized for delivering carrierdevices, surgical instruments, fixation devices, fixation tools,connecting devices, connecting tools, tissue, grafting material, orillumination devices, to a pathology location within the body cavity.The method may also include inserting additional elongated tubes withinadditional body cavities of the patient adjacent to the first and secondbody cavities. The method may also include making a second incision on asecond location of the patient's skin, then advancing a second guidewire through the second incision, through tissue underlying the secondlocation and into a second underlying bone, then forming the second bodycavity around the second guide wire and finally removing the first andsecond tubes from the first and second body cavities and closing thefirst and the second incisions.

Among the advantages of this invention may be one or more of thefollowing. The invention provides novel devices and methods forimproving percutaneous surgeries for all applications and approaches inthe body that previously required open surgery. These improvements willbe beneficial to both patients and surgeons in that this invention willreduce the technical difficulty of these operations, improvevisualization, decrease risks of iatrogenic injuries to vitalstructures, decrease length of hospitalization and associated costs,decrease operative time, decrease recovery time, and decreasepostoperative pain. This invention provides the ability to adjust thelength of the minimal access portals either inside or outside thepatient to account for the varying depth of the pathology within thebody. The graduated markers in millimeter increments etched on theoutside of the cannula allow a determination of the depth of thepathology relative to the skin thus allowing the user to makeadjustments to the fixation points such that they are aligned to thesame depth. The invention further allows fixing two pointspercutaneously along the lateral aspect of the spine by directly placingthe connecting device between the fixation points without visualizingthe entire connecting device or by coming in along an arc or usingfluoroscopic imaging. The invention also provides the ability tosequentially connect a fixation device percutaneously between more thantwo points simultaneously and only directly visualizing the fixationpoints and not the entire connecting device. This scaleable feature iscurrently a major limitation of other minimal access devices. Anotheradvantage of this invention is the ability to perform a direct approachto the fixation of two or more points with the option to place theconnecting device beneath the lumbodorsal fascia or through an incision,created by instruments in the lumbodorsal fascia between each fixationpoints rather than being confined to go beneath the fascia between thefixation points or through a larger opening in the fascia which requiresgreater tissue expansion and results in greater postoperative pain. Theinvention also provides a device that easily connects the portals at thesequential fixation points and simultaneously delivers objects such asconnecting devices, or tools between the fixation points even if thefixation points are not in a perfectly straight line. The invention alsoprovides the ability to lock the working cannula to the pedicle screwand is the first pedicle screw to feature an appendage for connecting apercutaneous device. It is the first device to allow easy retrieval of amedical device in contrast to the other systems that are designed forinsertion of medical devices without a method or features that aredesigned for retrieval of the device. The cannulae can be easily removedfrom the fixation points and have the ability to reconnect to thefixation points and remove the connecting device even after havingcompleted the surgery or after connecting the device to the fixationpoints and removing the cannulae. The invention also provides aside-working channel in addition to the central working channel to alloweasier placement of connecting devices between fixation points withoutobstructing the visual portal as in other devices with only a singleworking channel that also doubles as a visualization channel. Theinvention also provides a fixed or rotating apparatus at variouspositions on any of the working channels or portals that can be used foroptics, illumination, irrigation, or aspiration or combination thereof.The invention also provides a carrier device for carrying devices to beconnected at the fixation points of the cannulae. This carrier devicemay be made of a material that is stiff, malleable, flexible orexpandable at body temperature. By being malleable this carrier devicemay be used as a template on the skin surface between the cannulae priorto insertion and will be particularly beneficial when the cannulae donot line up in a straight line. The present invention has applicationsin a wide range of surgical procedures, and in particular in spinalprocedures such as laminotomy, laminectomy, foramenotomy, facetectomyand discectomy, fusions or disc replacements using an anterior,posterior, postero-lateral, or a lateral approach to the disc space,facet, laminas, pedicles, or transverse processes. The devices andinstruments of the present invention have application to surgicaltechniques that permit each of these several types of surgicalprocedures to be performed via a single or multiple sequential workingchannels. The present invention also has application to surgicaltechniques for preparing a disc space for insertion of an implant intothe disc space.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and description below. Other features, objectsand advantages of the invention will be apparent from the followingdescription of the preferred embodiments, the drawings and from theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the figures, wherein like numerals represent like partsthroughout the several views:

FIG. 1A is a top view of the back of a patient positioned prone on theoperating table in preparation for spinal surgery;

FIG. 1B is a top view of the patient's back with portals inserted in theareas of the pathology;

FIG. 2A is a perspective view of a portal with an adjustable length,according to this invention;

FIG. 2B is another perspective view of the portal of FIG. 2A;

FIG. 2C is a cross-sectional view of the outer and inner cannulae ofFIG. 2A;

FIG. 2D is a cross-sectional view of another embodiment of the outer andinner cannulae of FIG. 2A;

FIG. 3A-3C are perspective views of an assembled portal, according tothis invention;

FIG. 4 is a layered top view of the patient's back with incisions madeon the skin extending through the lumbodorsal fascia to the deeptissues;

FIG. 5 is a layered top view of the patient's back with incisions madeon the skin and guide wires placed percutaneously through the skin andinto the underlying vertebrae;

FIG. 6 is top view of the patient's back with portals placed in theopenings formed from the skin surface and extending deep into thepathology areas;

FIG. 7 is a top view of the patient's back as in FIG. 6 with a pair ofcurved scissors placed through a portal of this invention;

FIG. 8 is a top view of the patient's back as in FIG. 6 with a carrierdevice placed through a portal of this invention;

FIG. 9 is a top view of the patient's back as in FIG. 6 with a carrierdevice placed through a portal of this invention, the carrier devicecarrying a connecting rod for placement between adjacent vertebrae;

FIG. 9A is a cross-section of the front portion of a carrier device inthe open position;

FIG. 9B is a cross-section of the front portion of the carrier device ofFIG. 9A in the closed position;

FIG. 10 is a top view of the patient's back with two rod carrier devicesplaced in two different portals for inserting an entire rod in the areabetween the two portals, under the skin and lumbodorsal fascia andattaching it to the connection points;

FIG. 11 is a top view of a connecting rod that was placed in the slotsof three sequential pedicle screws using the portals of this invention;

FIG. 12 is a front view of a connecting articulating device that wasconnected to three sequential pedicle screws using the portals of thisinvention;

FIG. 13 is a perspective view of a connecting articulating device thatwas placed under the skin and lumbodorsal fascia and was connected tothree sequential pedicle screws using the portals of this invention;

FIG. 14 is a front view of a cannulated tissue dilator that when rotatedcreates a cylindrical space along its path;

FIG. 15 is a front view of a collapsible tissue dilator that can beinflated to create a space along its path;

FIG. 16 is a block diagram of a spinal operating procedure utilizing theportals of this invention;

FIG. 17A is a perspective view of another embodiment of a portal with anadjustable length, according to this invention;

FIG. 17B is a top view of the embodiment of FIG. 17A;

FIG. 18A is a perspective view of another embodiment of a portal with anadjustable length, according to this invention;

FIG. 18B is a top view of the embodiment of FIG. 18A;

FIG. 19A is a perspective view of another embodiment of a portal with anadjustable length, according to this invention;

FIG. 19B is a top view of the embodiment of FIG. 19A;

FIG. 20A is a perspective view of another embodiment of a portal with anadjustable length, according to this invention;

FIG. 20B is a top view of the embodiment of FIG. 20A; and

FIG. 21 depicts a perspective view, a top view, a front view and a sideview of a carrier device.

DETAILED DESCRIPTION

Referring to FIG. 1A, a patient 90 is positioned prone, lying flat on anoperating table 91 in preparation for a minimally invasive surgery(MIS). Locations 92 a-92 f are marked on the patient's lower backcorresponding to pedicle locations of adjacent vertebrae. For MISprocedures portals 94 a-94 f are inserted through skin incisionsperformed in the marked locations 92 a-92 f, respectively, shown in FIG.1B.

According to one embodiment of this invention, shown in FIG. 2A, andFIG. 2B, portal 94 a includes an outer elongated cannula 110 and aninner elongated cannula 120. Inner cannula 120 slides within outercannula 110 and is secured at different locations of the inner wall ofthe outer cannula 110, thereby forming a first working channel 115 withadjustable length. This is especially desirable for reaching locationswithin the patient's body corresponding to the outer locations 92 a-92f, that are at different distances from the patient's skin 70. Outercannula 110 has millimeter markers 192 etched on the outside surface toallow determination of the depth of the pathology (shown in FIG. 17A).Portal 94 a has an outer diameter sized for percutaneous placementwithin the patient's body. In one example, the outer diameter of portal94 a, as defined by the outer diameter 111 a of the outer cannula 110,is 20 mm. Outer cannula 110 includes two elongated pieces 10 a, 110 b,extending from the distal end 113 of the main hollow cylindrical body114 and forming an opening 118 a between them. The proximal end 112 ofthe hollow cylindrical body 114 has a circular opening with an innerdiameter 111 b, and the previously mentioned outer diameter 11 a. In oneexample, the outer cannula 110 has a length 116 of 40 mm, an innerdiameter 111 b of 18 mm and an outer diameter 111 a of 20 mm. The outercannula further includes a side portal 130 and an opening 132 locatedopposite to the side portal thereby defining a second working channel135 (shown in FIG. 3C). The second working channel 135 communicates withthe first working channel 115. In other embodiments, more than one sideportals are included and may be located at any location along the outeror inner cannula or may be detachable. In another embodiment elongatedpieces 10 a and 110 b may extend directly from the base of side portal130. In another embodiment side portal 130 may communicate directly withthe proximal opening of cylindrical body 114. In the embodiment of FIG.2A, side portal 130 is fixed at an angle relative to the outer cannula110. In other embodiments, side portal 130 may be hinged so that it canbe placed at variable angles along the outer cannula 110. Side portal130 functions as an automatic stop against the patient's skin 70, whilethe inner cannula 120 slides within the outer cannula 110 and elongatesin order to reach the location of the pathology within the patient'sbody. Accordingly, the exposed length of the various outer cannulaeabove the skin may remain the same while the entire length of theportals variably elongates. It is important for the surgeon to have aconsistent height of the cannula above the skin surface which mayotherwise vary with different patient body habitus.

The inner cannula 120 includes a main hollow cylindrical body 122 andtwo elongated pieces 120 a, 120 b extending from the proximal end 123 ofthe main body 122. An opening 118 b is formed between the two elongatedpieces 120 a, 120 b. In one embodiment, inner cannula 120 furtherincludes a slot 121 at the distal end of the main body 122 thatfunctions as a docking element for attaching a device or a connectingelement to the distal end of the itmer cannula 120. In the example ofFIG. 2A, the element shown 140 is a pedicle screw with an extension 141that fits within the slot 121.

In one example, inner cannula 120 has a length 124 of 40 mm, an innerdiameter 127 of 17 mm, and an outer diameter 128 of 17.75 mm. In otherembodiments the outer diameter 128 may be in the range of 17.5 to 18 mm.In the embodiment of FIG. 2A, inner cannula 120 and outer cannula 110have uniform inner and outer diameters. In other embodiments, thediameters may be non-uniform and the cannulae may be tapered at one orboth ends. In other embodiments the opening 118 b in cannula 120 mayextend through the distal ends of both sides of cannula 120 withoutconnecting the elongated pieces 120 a and 120 b or only on one sideconnecting either 120 a or 120 b.

Referring to FIG. 2C, the outer cannula 110 further includes anappendage 119 formed within the inner wall 117 of the outer cannula 110and extending the entire length 116 of the cannula 110. Appendage 119slides within a groove 129 formed on the outer wall 167 of cannula 120.Groove 129 extends the length 124 of the inner cannula 120 ending priorto reaching the top of cannula 120 so that there is a stop to completeseparation of the cannulae as they elongate against each other andallows removal of the cannulae as one piece. Cannula 120 may have a lipat the top edge which overhangs to fit within the space within the wallof cannula 110 and stops against a ledge at the bottom of cannula 110.Alternatively, the outer cannula 110 may have a groove 109 in the innerwall 117 and the inner cannula 120 may have an appendage 139 in theouter wall 167 and the appendage 139 of the inner cannula 120 may slidewithin the groove 109 of the outer cannula 110 in a tongue and groovetype fashion, as shown in FIG. 2D. Groove 109 ends prior to reaching themost distal surface of the outer cannula 110 so that there is a stop tocomplete separation of the cannulae as they elongate against each otherand allows removal of the cannulae as one piece. In one embodiment theinner groves 109 and 129 may have serrations that allow a ratchet-typeincremental elongation and shortening of the combined lengths of thecannulae 110 and 120. The ratchet-type mechanism also functions as aheight securing mechanism which is an adjunct to the automatic heightadjustment that occurs between the side portal 130 contacting the skinand the pedicle screw 140 contacting the vertebra as the cannulaeelongate against each other. In other embodiments, the surfaces of theinner wall 117 and outer wall 167 are smooth.

The portal 94 a dynamically adjusts its height automatically as thepedicle screw 140 advances within the pedicle since the distal end 122of the inner cannula 120 is fixed to the screw 140 and each cannula 110,120 is permitted to slide relative to each other. In another embodimentthe inner cannula 120 slides within a space formed between the inner andouter diameter of cannula 110. Referring to FIGS. 17A and 17B, portal400 includes an outer hollow cannula 110 and an inner hollow tube 190placed with the hollow outer cannula 110. The diameter of the inner tube190 is smaller than the inner diameter of the outer cannula 110 and aspace 198 is formed between them. Inner cannula 120 is sized to fitwithin the space 198 and to slide against the inner wall 117 of theouter cannula 110 and the outer wall 199 of the inner tube 198. Theinner wall 117 of outer cannula 110 includes a groove 109 a extendingthe entire length 116 of the cannula 110 and the outer wall of the innercannula 120 includes an appendage 139 a. Appendage 139 a slides withinthe groove 109 a in a tongue and groove type configuration. Appendage139 a extends the length 124 of the inner cannula 120 ending prior toreaching the top of cannula 120 so that there is a stop to completeseparation of the cannulae as they elongate against each other andallows removal of the cannulae as one piece. A second appendage 139 bplaced diametrically opposite the first appendage 139 a on the outerwall of the inner cannula 120 slides within a second groove 109 b placeddiametrically opposite the first groove 109 b on the inner wall of theouter cannula 110.

Referring to FIGS. 18A and 18B, in another embodiment, the inner cannula120 slides within a space 198 formed between the cylindrical inner wall117 of the outer cannula 110 and two planar inner walls 194 a and 194 bextending from and connecting opposite sides of the cylindrical wall117. In yet another embodiment, shown in FIGS. 19A and 19B, portal 420includes an outer cannula 110 and two inner cannulae 120 a and 120 b.Inner cannula 120 a slides against the inner cylindrical wall 117 of theouter cannula 110, against four planar walls 194 a, 194 b, 194 c, of theouter cannula 110 and against the outer cylindrical wall of the innercannula 120 b. Inner cannula 120 b slides against the inner cylindricalwall of inner cannula 120 a.

In another embodiment the outer cannula 110 slides within the innercannula 120 (not shown). In another embodiment, shown in FIGS. 20A and20B, the portal 440 extends in a telescopic fashion as one piece. Inthis embodiment, the length is adjusted by unscrewing the outer cannula110 or screwing the inner cannula 120 in each case relative to eachother.

Referring to FIG. 3A, FIG. 3B, and FIG. 3C inner cannula 120 is rotatedrelative to the outer cannula 110 so that openings 118 a and 118 b arealigned, forming an elongated pass-through slot 118 when the portal 94 ais assembled. Pedicle screw 140 includes an appendage 141 and isattached to the inner cannula 120 by engaging the appendage 141 to theouter cannula slot 121, as shown in FIG. 3B. In this embodiment accessto the pedicle screw is achieved through the first working channel 115.In another embodiment the pedicle screw is engaged as an interferencefit within the distal end of cannula 120. In either case a screw driveor pushing device fits into the head of the pedicle screw and stabilizesthe screw, if the head is multiaxial, while it is being inserted deepinto the body cavity.

Other instruments or devices may be inserted either through the firstworking channel 115 or the second working channel 135, shown in FIG. 3C.A detachable optical and/or illumination device 194 is interferencefitted to the proximal end 112 of the outer cannula 110 and is capableof rotating around an axis passing through the first channel 115. Theoptical and/or illumination device may be a light source and/or anoptical fiber that has one end connecting to a light source and a secondend placed in the vicinity of the pathology area, thereby providingdirect illumination and visualization of the pathology area. In otherembodiments the illumination device may be fitted through the sideportal 130 or through an inverted L-shaped appendage protruding from theinner wall of the outer cannula 110 into the first working channel andconsisting of a hollow inner core that communicates with the inner andouter diameters of the outer cannula 110 and is sized to receive theoptical device and/or the light source. Alternatively, the opticaldevice may be similarly connected to inner cannula 120.

Customized instruments are also provided for insertion within the firstworking channel 115 or the second working channel 135. Referring to FIG.7, a customized curved pair of scissors 150 is inserted through thefirst working channel 115 of portal 94 c. In other embodiments scissors150 are inserted through the side portal 130. Scissors 150 is used toincise the lumbodorsal fascia 75 in the area 72 b between two adjacentportals 94 c and 94 b for opening a path 74 b between them. This path 74b is then used for delivering and placing bone graft, connectingelements, such as rods, plates, wires, or articulating versions thereof,for connecting the adjacent vertebrae 82 c and 82 b of the spine 80. Theconnecting elements are then secured to the corresponding vertebrae 82c, 82 b via screws placed through the first working channels 115 of thecorresponding portals 94 c, 94 b. Similarly, paths 74 a, 74 c, 74 d maybe opened in the areas 72 a, 72 c, 72 d between the adjacent portals 94b and 94 a, 94 d and 94 e, and 94 e and 94 d, respectively. Other typesof incision instruments may also be used, including curved scalpels,among others. In another embodiment, the curved scissors 150 is insertedthrough the working channel 135.

Referring to FIG. 8, FIG. 9, and FIG. 21, a customized curved carrierinstrument 160 is inserted through the opening of the second workingchannel 135 of portal 94 c and passes through the opened path 74 bbetween the adjacent portals 94 c, 94 b. Instrument 160 enters the firstworking channel of portal 94 b through the side slot 118. Instrument 160is used for delivering the above mentioned bone graft, connectingelements 170, screws or biological materials in the areas between theadjacent portals. The front portion 162 of the carrier instrument 160includes an elongated semi-cylindrical groove for carrying theconnecting elements 170. In another embodiment, the front portion 162may be a cylindrical tube as one piece or two separate pieces which canrotate relative to each other to form a cylinder or a half cylinder,shown in FIG. 9A and FIG. 9B. The tip of the carrier instrument 160 maybe shaped as the tip of a bullet or a canoe to shield the devices beingcarried from the surrounding soft tissues as the carrier device isforced through the tissues between the adjacent portals 94 c, 94 b. Thecarrier instrument 160 may be flexible, malleable, or rigid and may beexpandable at body temperature.

Referring to FIG. 14, a customized tissue dilator instrument 200 isprovided for developing a path in the soft tissues from the skin surface70 of the patient's body 90 to a desired depth within the patient'sbody. Instrument 200 includes a handle 220 that connects to a shaft 230and the shaft 230 connects to a paddle 250. An elongated cannula 240extends the entire length 202 of the instrument 200 and connects anopening 204 at the proximal end of the handle to an opening 260 at thedistal end of the paddle 250. By rotating the paddle either clockwise oranticlockwise and moving up or down from the skin 70, respectively, tothe deeper layers, a cylindrical path is created with diameter equal tothe width of the paddle 250.

Referring to FIG. 15, another customized tissue dilator instrument 210is used for developing a path in the soft tissues from the skin surface70 of the patient's body 90 to a desired depth within the patient's bodyand for removing the soft tissues along the opened path. Instrument 210includes a handle 227 that connects to a shaft 232 having a cannula 233.Cannula 233 extends the entire length of the instrument 212 and has aproximal opening 234 and a distal opening 231. Shaft 232 is surroundedby an inflatable balloon-type component 229 which when inflated througha connected tube 228 and moved up and down from the surface 70 to thedeeper layers, clears a cylindrical space in the soft-tissues along thepath of the instrument equal in diameter to the largest diameter of theinflated component 229.

The steps of a spinal surgical procedure 300 in accordance with oneaspect of the present invention are depicted schematically in the blockdiagram of FIG. 16 and figuratively in FIG. 1 to FIG. 15. The presentembodiment of the invention permits a substantially mid-line or medialposterior or postero-lateral approach to the spine but other approachesto other parts of the body are understood to be feasible with thisinvention. Referring to FIG. 16, FIG. 1 and FIG. 4, in a first step ofthe technique, small incisions are made in the patient's skin 70 alongthe spine 80 creating skin openings 92 a-92 f (302). Next, guide wires96 a-96 f are advanced through the skin openings 92 a-92 f,respectively, through the underlying tissue and into the bony anatomy ofa vertebral element such as a pedicle (304). The wires are insertedunder fluoroscopic vision or as an open procedure under direct vision.In the subsequent step, a tissue dilator as depicted in FIG. 14 and FIG.15 is advanced over the guide wires (306). The dilator is eitherinflated (as in FIG. 15) or rotated (as in FIG. 14) and withdrawn slowlyto develop a channel from the skin to the fixation point of the guidewire. In the next step, a fixation device such as a pedicle screw 140 isattached to each of the working portals 94 a-94 f and secured via thelocking mechanism 141, as depicted in FIG. 2A and FIG. 3A (308). Acannulated screwdriver or an elongated instrument is connected to thefixation device 140 and combined with the portal assembly is advancedthrough the incision (312). The portal assemblies 94 a-94 f includingthe pedicle screw 140 and screwdriver are inserted over the guide wires96 a-96 f, respectively, and into the bone as depicted in FIG. 6 (310).Alternatively, a second tissue dilator having a cylindrical shapesimilar to the portal assembly but with a larger diameter and with anopening slot running unilaterally along its entire length may beinserted through the skin opening and left in place so that the portalassembly can be inserted inside of this second dilator therebypreventing tissue being caught within the portal assembly. The seconddilator can then be removed when the portal assembly is inserted bysliding the second dilator around the portal assembly via the openedchannel. Once the working portals 94 a-94 f rests against the patient'sskin 70, the cannulae 110 and 120 will start to slide with respect toeach other as the fixation device 140 advances through the soft tissuesuntil the desired depth is reached (314). This is a unique feature ofthis invention that will significantly improve the ease of performingpercutaneous surgery since there is no need to replace the fixed lengthportals to achieve the right depth into the patient's body or attachother cannulae to increase the length of the main working channel. Incases of thin patients portals with fixed length usually protrude highabove the level of the patient's skin and require external support forstability. This invention does not require an external support for theportal because the length of the protruding portal is always constantbecause the portion beneath the skin is adjustable. However, an externalsupport may be attached to either the main portal or the side workingportal for added stability. Once the portals are in position, the guidewires 96 a-96 f are removed (314). The above steps are repeated for asmany pedicle screws and openings that are required (315). A pair ofcurved facial scissors 150 or curved scalpel is then inserted throughthe working channel 115 of portal 94 c or through channel 135 of sideportal 130 and advanced beneath the patient's skin 70 while cuttingthrough the lumbodorsal fascia 75 until the scissor tips enter the nextadjacent portal 94 b through the slot 118, as in FIG. 9 (316). At thispoint the lumbodorsal fascia is completely discontinuous in the area 72b between the two portals 94 c and 94 b. A carrier device 160 is theninserted through channel 135 of side portal 130 across the soft tissueseither above or below the level of the lumbodorsal fascia 75 until thetip of the carrier enters the next adjacent portal 94 b (318). Thecarrier device 160 has a semi-cylindrical front portion 162 that is usedto support various objects that need to be inserted into the pathologyareas. In the example of FIG. 9, a connecting device 170, such as acylindrical rod, plate, articulating device, or biologic substances isplaced in the semi-cylindrical front portion 162 either before insertionor after insertion and is brought in the tissue area between portal 94 cand 94 b. In other examples, the front portion 162 has a fullcylindrical shape or includes two semi-cylindrical segments 162 a and162 b that can open or close to form either an open semi cylinder or aclosed cylinder, as shown in FIG. 9A and FIG. 9B, respectively. Thisstep can be repeated between multiple adjacent portals or across sets ofportals for segmental fixation as shown in FIG. 11, FIG. 12 and FIG. 13.After the connecting device 170 is engaged within the portals, thecarrier device 160 is retracted from the portals and the connectingdevice 170 is then inserted to the base of the portals or until itengages the fixation elements 140, such as a pedicle screw, as shown inFIG. 11-13 (322). Pushers 164 are available to apply force to theconnecting device 170 as it advances through the soft tissues. Thistechnique allows the connecting device 170 to approach the fixationpoints in a direct fashion rather than indirectly at an angle orindirectly via a predetermined arc. This technique also only uses directvision at the fixation points while not seeing the portion of theconnecting device between the fixation points. This diminishes the sizeof the soft tissue dissection and trauma as well as the incision size.Once the connecting device is engaged to the fixation points, lockingscrews are then used to secure the connecting device to the fixationpoints (322). The main tube is pushed downwards and turnedcounterclockwise or clockwise to disengage the appendage 141 from theslot 121 (324). It is understood that the slot may be vertical only orhorizontal only or a combination of the two or other configurations notspecified in this invention. The tube is then removed from the incisionand the incision closed in a standard fashion (324).

One of the unique features of this invention is the ability to engageand disengage the portals to and from the fixation devices 140,respectively, at any point during the operating procedure. In oneexample, the dilator device of FIG. 15 is placed in the depth of theincision and inflated to reopen the path to the fixation device 140. Theportal 94 a is replaced over the fixation device 140 and engages theappendage 141 on the fixation device 140, which in this case is alocking screw. The locking screw is then removed. This process is thenrepeated for as many fixation points as necessary. The connecting device170 is either advanced laterally to disengage one or more fixationpoints 140 a-140 c or it is grasped at each fixation point under directvision and advanced upwards. The carrier 160 is then advanced beneathone end of the connecting device 170 and then the connecting device isgrasped at that end and pulled diagonally along the carrier 160 out ofthe incision through the end of the working portal 94 b. With theportals engaged the procedure can be repeated from any point accordingto the sequence described above.

Once the main assembled portals are fixed to the appropriate depth, anoptic and or illumination device 194 can be connected at varyinglocations on cannula 110, 120 or working channel 135. In one specificembodiment, the optic or illumination device is most preferably a fiberoptic, although a rod lens scope or other viewing scopes may beutilized.

Because the portal is freely situated within the patient's skin and softtissues, it can be manipulated to be centered over the target region.Repositioning of the portal can be performed manually under fluoroscopicguidance or be fitted with a position sensing devices, such as LEDs, inorder to be guided stereotactically. Once the portal is appropriatelypositioned a variety of procedures using a variety of instruments can beperformed through the main working channel 115 or the side channel 135.It is understood that these various tools and instruments are designedto fit through the working channels. For instance, in one specificembodiment, the working channel 115 through the cannulae 110 and 120have a maximum inner diameter of 13 mm and the working channel 135 amaximum diameter of 10 mm. The present invention is not limited to thediameters mentioned for the working channels, since the dimensions ofthe components will vary depending upon the anatomy of the surgical siteand the type of procedure being performed and as such the channels willvary.

While the present invention permits the surgeon to conduct surgicalprocedures in the working channels under a dry environment, irrigationmay be provided separately through the working channel 135 to keep thevisualization space clear. Separate or combined irrigation andaspiration elements can also be inserted through the working channel 135or the main channel 115 as required by the procedure. In anotherembodiment the irrigation and aspiration elements may be combined withthe optic and or illumination assembly or some combination thereof.

Other embodiments are within the scope of the following claims. Forexample, the cannulae may have other cross-sections such as rectangularor square. The cannulae may be flexible or semi rigid. The devices maybe made of metal such as stainless steel, titanium, plastic, rubber,graphite, glass, expandable materials under body temperature, or otherradiolucent materials.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A method for restricting relative motion between a first vertebra, asecond vertebra, and a third vertebra of a patient, the methodcomprising: anchoring a first connecting element on the first vertebra;anchoring a second connecting element on the second vertebra; anchoringa third connecting element on the third vertebra; inserting a leadingend of a rod through skin of the patient; moving the leading endunderneath an unbroken portion of the skin; and securing the rod to thefirst, second, and third connecting elements.